1. Field
This application relates generally to wireless communication and more specifically, but not exclusively, to synchronizing wireless nodes.
2. Introduction
A wireless communication system may be deployed in various ways depending on the requirements of the intended application. For example, a planned deployment may be utilized for an application such as a cellular network where seamless connectivity is desired over a relatively wide area. To reduce interference in such a network, the channel or channels used by a given wireless device (or set of wireless devices) may be defined throughout the network. In addition, to further control interference in the network the wireless devices may communicate via designated timeslots whereby a given wireless device may transmit data during certain timeslots and receive data during other timeslots.
A more flexible deployment scheme may be used for an application such as a local area network that supports different types of wireless devices having different types of communication capabilities. For example, in such a network a set of wireless devices may unilaterally select their operating channel. In addition, the wireless devices may not use a timeslot structure for transmitting and receiving data. For example, in such a system a given wireless device may transmit data any time the selected channel is available. Here, an appropriate channel contention mechanism may be employed to prevent neighboring wireless devices from unduly interfering with one another.
In practice, the above deployment schemes may have certain disadvantages due to tradeoffs that may be made to provide a given type of service. For example, due to the relative complexity of centralized planning, setting up a planned wireless wide area network may be relatively expensive and time consuming. Hence, such a scheme may not be well suited for “hot spot” deployments. On the other hand, an unplanned wireless local area network may not achieve the same level of spatial efficiency (bits/unit area) as a planned network. In addition, interference mitigation techniques that may be used in unplanned networks may result in poor utilization, limited fairness control, and susceptibility to hidden and exposed nodes.